1. Field of the Invention
The present invention relates to the use of reaction products of polymers of C.sub.2 -C.sub.6 -olefins having an average degree of polymerization P of from 5 to 100 and oxides of nitrogen or mixtures of oxides of nitrogen and oxygen as additives for fuels, and to fuels which contain these reaction products and are intended for gasoline engines. The present invention furthermore relates to nitro-containing alkenes and aminoalkanes which are derived from these reaction products, their use as additives for fuels and for lubricants and fuels for gasoline engines and lubricants which contain these additives.
2. Discussion of the Background
The carburettor and intake system of gasoline engines as well as injection systems for fuel metering in gasoline and diesel engines are contaminated by impurities which are caused by dust particles from the air, uncombusted hydrocarbon residues from the combusting space and crank case vent gases passed into the carburettor.
The residues shift the air/fuel ratio during idling and in the lower part-load range so that the mixture becomes richer, the combustion is more incomplete and in turn the amounts of uncombusted or partially combusted hydrocarbons in the exhaust gases become larger and the gasoline consumption increases.
It is known that, in order to avoid these disadvantages, fuel additives can be used for keeping valves and carburettors or injection systems clean. (M. Rossenbeck in Katalysatoren, Tenside, Mineraloladditive, Editors J. Falbe and U. Hasserodt, page 223 et seq., G. Thieme Verlag, Stuttgart, 1978).
Depending on the mode of action but also on the preferred site of action of such detergent additives, a distinction is now made between two generations of such assistants.
The first generation of additives could only prevent the formation of deposits in the intake system but could not remove existing deposits, whereas the additives of the second generation can do both (keep-clean and clean-up effect) and can do so because of their excellent heat stability, in particular in zones of relatively high temperatures, ie. in the intake valves.
The molecular structural principle of fuel detergents can generally be described as the linking of polar structures with generally high molecular weight, nonpolar or lipophilic radicals.
Members of the second generation of additives are often products based on polyisobutenes in the nonpolar moiety. Among these in turn, additives of the polyisobutylamine type are particularly noteworthy.
U.S. Pat. No. 3,576,742 (1) describes products of branched long-chain aliphatic olefins, for example polypropylene, polyisobutylene or copolymers or ethylene and isobutylene, and oxides of nitrogen as detergents for lubricants.